<template>
  <div>
    <canvas id="myCanvas"
            @click="changeVeri"></canvas>
  </div>
</template>
<script>
export default {
  name: "veri",
  data () {
    return {
      veri: ""
    }
  },
  created () {
    this.getVeri();
  },
  beforeMount () {

  },
  mounted () {

  },
  methods: {
    changeVeri () {
      this.getVeri();
    },
    // 获取验证码的函数
    getVeri () {

      this.axios({
        url: "/VueHandler/AdminLoginAndRegHandler?action=verification",
        method: "get"
      }).then(res => {
        console.log(res)
        this.draw(res.data.data) //把返回的验证码 用canvas绘制
      })
    },
    randomColor () {//随机颜色的函数
      var r = Math.floor(Math.random() * 256);
      var g = Math.floor(Math.random() * 256);
      var b = Math.floor(Math.random() * 256);
      return "rgb(" + r + "," + g + "," + b + ")";
    },
    draw (aCode) {  //传入验证绘制到canvas code ="dasf"
      var canvas_width = document.getElementById("myCanvas").offsetWidth;
      var canvas_height = document.getElementById("myCanvas").offsetHeight;
      var canvas = document.getElementById("myCanvas"); //获取到canvas的对象，演员
      var context = canvas.getContext("2d"); //获取到canvas画图的环境，演员表演的舞台
      canvas.width = canvas_width;
      canvas.height = canvas_height;
      // var sCode =
      // "a,b,c,d,e,f,g,h,i,j,k,m,n,p,q,r,s,t,u,v,w,x,y,z,A,B,C,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,W,X,Y,Z,1,2,3,4,5,6,7,8,9,0";
      // var aCode = sCode.split(",");
      // var aLength = aCode.length; //获取到数组的长度

      for (var i = 0; i < 4; i++) {
        //这里的for循环可以控制验证码位数（如果想显示6位数，4改成6即可）
        // var j = Math.floor(Math.random() * aLength); //获取到随机的索引值
        // var deg = Math.random() * 30 * Math.PI / 180;//产生0~30之间的随机弧度
        var deg = Math.random() - 0.5; //产生一个随机弧度
        var txt = aCode[i]; //得到随机的一个内容
        // show_num[i] = txt.toLowerCase();
        var x = 10 + i * 20; //文字在canvas上的x坐标
        var y = 20 + Math.random() * 8; //文字在canvas上的y坐标
        context.font = "bold 23px 微软雅黑";

        context.translate(x, y);
        context.rotate(deg);

        context.fillStyle = this.randomColor();
        context.fillText(txt, 0, 0);

        context.rotate(-deg);
        context.translate(-x, -y);
      }
      for (let i = 0; i <= 5; i++) {
        //验证码上显示线条
        context.strokeStyle = this.randomColor();
        context.beginPath();
        context.moveTo(
          Math.random() * canvas_width,
          Math.random() * canvas_height
        );
        context.lineTo(
          Math.random() * canvas_width,
          Math.random() * canvas_height
        );
        context.stroke();
      }
      for (let i = 0; i <= 30; i++) {
        //验证码上显示小点
        context.strokeStyle = this.randomColor();
        context.beginPath();
        let x = Math.random() * canvas_width;
        let y = Math.random() * canvas_height;
        context.moveTo(x, y);
        context.lineTo(x + 1, y + 1);
        context.stroke();
      }
    }
  },
}
</script>
<style lang="less">
#myCanvas {
  width: 130px;
  height: 38px;
  background: white;
}
</style>